Well, you're right; it's a keeper. I believe they were made in Japan by National/Panasonic, and they're very high end framesets. Notice the sidebar:
"Prologue - A 1987 World Champion in its very first year."
Here's the 1988 Prologue catalog page from the lightweight catalog. I don't believe there were any significant changes made from '87 through '89.
Here's the frameset page from the '89 Parts & Accessories catalog.
